Filmgoers today would probably find it hard to believe the complete innocence with which the earliest audiences encountered Ridley Scott's Alien 38 years ago. The initial ads were so discreet that all you really knew going in was that it took place on some kind of spacecraft and — based on the poster — somehow involved an egg. Three sequels, two prequels and a variety of multimedia spin-offs later, the balance has shifted, and the initial shocks of the original — exploding chests and face-hugging, acid-drooling creatures — have become the trademarks of the series, a comfortable routine of cat-and-mouse suspense and space gore.

Alien: Covenant is both a typical entry into the Alien cycle and a sequel to Scott's 2012 film Prometheus, a more conventional science fiction film that dropped hints about the origins of the creepy little monsters. (Don't worry, I couldn't remember much about Prometheus either.)

The film begins on a spaceship packed to the rafters with sleeping astronauts and frozen embryos headed off to colonize a planet called Origae-6. When the captain (James Franco, keeping up his annual quota of film cameos) is killed in some sort of space storm, the remaining crew, led by the first mate (Billy Crudup), the captain's widow (Katherine Waterston), the requisite impulsive space cowboy (Danny McBride), and the impeccably polite android Walter (Michael Fassbender), pick up a signal from an unknown but surprisingly habitable planet, although it's littered with corpses as far as the team can see.

Things turn bad quickly, as the crew is simultaneously befriended by the sole semi-human resident, the suspiciously polite android David (also Fassbender, reprising his role from Prometheus), and then depleted by the various species of aliens he appears to be breeding.

For a typical Alien movie, this would be the point where you just sit back and watch the body count rise as the constantly transforming space creatures gnaw and impale their way (often literally) through their human prey. But this isn't a typical Alien movie, it's a Ridley Scott film, and a continuation of the ponderous Prometheus — so there's a great deal of conversation about life and mortality, references to Milton and whatever else the screenwriters can remember from Philosophy 101.

Billy Crudup wears the perpetually pained expression of a man who just woke up from years of cryo-sleep on an empty stomach and grumbles that he doesn't get the respect he deserves because "he's a man of faith," a plot point that is completely abandoned in the mayhem that follows. Walter, the Bad Android, rambles on about the respective attributes of human, machine and alien; he's like an extremely chatty mad Nazi scientist in a 1940s movie serial. He suffers a major burn when David, the Good Android, schools him on the authorship of every science fiction villain's favorite poem,"Ozymandias" ("Look on my works, ye mighty, and despair"). Their conflict leads to a scene of dueling Fassbenders that is either the height of camp or a landmark in cinematic narcissism. Maybe both.

The film brings to mind what I call the Kubrick Corollary: Every director of a serious science fiction film thinks they're making their own 2001; no film studio will ever again allow a director to make their own 2001. And if you can put aside its grand ambitions, Alien: Covenant has all of the trappings you could want from an Alien movie. Torsos explode. Monsters snap and growl. At least one crew member is foolish enough to stop and take a shower while all of this is going on. The big action scenes work fairly well, and the blood-and-guts scenes, while no longer having the element of surprise, are suitably gruesome.

There's even a small moment at the end that recalls the climax of Curtis Harrington's 1966 Planet of Blood, nicely circling the series back to its original inspiration. The humans are reasonably heroic and the aliens ... well, they pop out with their usual efficiency. After 38 years and a half-dozen incarnations, that's about all you should really expect from an Alien film.